<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>includeDefaultValues</title>
  <style>
    #canvasBox {
      border: 1px solid #ccc;
    }
  </style>
</head>
<body>
  <div>
    <button onclick="toObject()">toObject</button>
  </div>
  <canvas id="canvasBox" width="600" height="600"></canvas>

<script src="../../script/fabric.js"></script>
<script>
  window.onload = function() {
    // 使用 元素id 创建画布，此时可以在画布上框选
    canvas = new fabric.Canvas('canvasBox', {
      width: 400,
      height: 400,
      // includeDefaultValues: true // 默认 true
      includeDefaultValues: false // 指示toObject/toDatalessObject是否应该包含默认值，如果设置为false，则优先于对象值
    })

    fabric.Image.fromURL('../../images/bg.jpg', img => {
      canvas.setBackgroundImage(img)
      canvas.renderAll()
    })

    // 圆形
    circle = new fabric.Circle({
      id: 1,
      name: 'circle',
      top: 60,
      left: 60,
      radius: 30, // 圆的半径 30
      fill: 'yellowgreen'
    })

    // 矩形
    rect = new fabric.Rect({
      id: 2,
      name: 'rect',
      top: 30, // 距离容器顶部 60px
      left: 100, // 距离容器左侧 200px
      fill: 'orange', // 填充a 橙色
      width: 60, // 宽度 60px
      height: 60 // 高度 60px
    })
    
    // 将矩形添加到画布中
    canvas.add(circle, rect)
  }

  function toObject() {
    const res = canvas.toObject()
    console.log(res)
  }
</script>
</body>
</html>